Question

If the difference in the compound and simple interest on a certain sum for 2 years at the rate of 4% per annum is rs. 1,the sum is

Answer 1

the equation for si and ci difference for 2 yrs is
$pr {}^{2} \div 100 {}^{2} \\ \\ \\ where \: p \: is \: principle \: amd \: r \: is \: rate$
so here
$(p4{}^{2}) \div 100 {}^{2} =1 \\ \\ \\ \ \\ i \:e \: \: (p \times 16) = 10000 \\ \\ p = (10000 \div 16) \\ \\ \\ p = 625$


ie the sum is 625